As media outlets have noted the support of evangelical Christians Alistair Burt and Desmond Swayne as well as the Catholic Cabinet minister Patrick McLoughlin is an indication of the group's broad base. More high-profile supporters will be announced in the coming days and weeks.

Yesterday evening proved to be a topsy-turvy experience for the leader of the Scottish Tories, Ruth Davidson. The lesbian MSP was named Politician of the Year by the homosexual campaigning group Stonewal. A spokesman for Stonewall told the BBC why Ms Davidson had been recognised:

"As Britain's first openly gay leader of a mainstream political party, Ruth has shown thousands of young gay Scots that they can aspire to be what they want to be."

But Ms Davidson's moment in the spotlight couldn't have been comfortable. She was booed at the awards ceremony after she criticised Stonewall's decision to introduce a 'bigot of the year' category and award it to the leader of Scotland's Catholics, Cardinal Keith O'Brien. "Where I disagree with Stonewall," she said, "is the need to call people names like 'bigot'." She continued:

"It is simply wrong. The case for equality is far better made by demonstrating the sort of generosity, tolerance and love we would wish to see more of in this world. There are many voices in this debate and just as I respectfully express my sincerely held belief that we should extend marriage to same-sex couples, I will also respect those who hold a different view."